Replies

1. 
   SCFrankland | Jan 30, 2004 12:52am | #1

   It depends on the finish mostly. Most surfaces are done with a handplane and that is it. If I do break out the sand paper then I will go to 180-220 and sometimes maybe 320. After the first coat is on I will go over the surface with with 400 and then 600 for the next coat.

   Scott C. Frankland

   Scott's WOODWORKING Website

   "He who has the most tools may not win the race of life but he will sure make his wife look like a good catch when she goes to move on."

2. 
   Alan | Jan 30, 2004 03:21am | #2

   Aguita,

   We have this discussion every so often, and they all end with the same conclusions.

   As Scott said, when you're sanding raw wood there's no point in going farther than 180 or 220 grit.  Sometimes it might serve some purpose to go to a little finer grit paper, but using a finer grit than 280 or 320 serves no useful purpose--and may, in fact, lead to finishing woes by burnishing the wood and filling the grain with extremely fine dust.  For any application that I know of (I am definitely NOT omniscient--a fact that I reveal constantly) there's definitely no point in using 1000 or 1500 grit paper.

   As for scuff sanding between finishing coats, I use the finest paper that will flatten the surface and remove the little nits and bits and snits.  Which grit, of course, depends on the finish, whether you're sanding the first coat or the last, and so on.  For a first coat of varnish, for example, I usually try about a 320 or 400 grit paper.  For shellac, which is a thinner film than varnish, I will start with a finer paper, a 600 grit or so.

   Alan

3. 
   RANGERP75R | Jan 30, 2004 07:18pm | #3

   aguita

      Agree with Scott and Alan.

   sarge..jt

   Proud member of the :  "I Rocked With ToolDoc Club" .... :>) 

4. 
   forestgirl | Jan 30, 2004 07:48pm | #4

   I'm no expert, but have followed past discussions and it certainly would seem anything over 320 is probably wasted time, and may even cause problems with the subsequent finish due to burnishing of the wood.  Wetsanding oil finishes may be an exception.  I've read a number of posts/articles that indicate wetsanding to 400 grit.  I've mostly gone to 320 for wetsanding.

   Take a look in the gallery at Gecko's "Reproduction cabinet" thread -- I think he used 1500 for the final sanding of the lacquer, before waxing. 

   forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

5. 
   HowardAcheson | Jan 30, 2004 09:42pm | #5

   Sanding wood--hard or soft--beyond 220 does little more than burnish the wood making staining difficult. This is particularly true if you are using a pigment stain which sits on the surface and relies on "nooks and crannies" to impart color. Softer more porous woods can be sanded to to 220 but harder less absorbent woods may stain best if only sanded to 150.

   A number of years ago a shop I was involved with did series of adhesion tests with various finishes and sealers. As part of this test we explored adhesion based on sanding grit. We found about the same adhesion up to 180 - 220. Beyond 220 adhesion dropped off due to burnishing of the underlying wood particularly when non-linear machine sanders were used. This was tested on birch panels. We also found that the resulting smoothness of the first coat of finish was not materially affected by the smoothnes of the underlying wood for sandpaper grits between 150 - 220.. Thin finishes such as lacquer could be affected by grits less than 180. The smoothest surface substrate for final finishes was obtained by sanding lightly after the first coat of finish was applied and dry. Which makes the case for a thinned first coat of finish.

   So our conclusion was that sanding beyond 180-220 was a waste of time and could be actually detrimental. But, there was a big appearance affect if the surface was not hand sanded in the direction of the grain using the highest grit used on the sanding machine. A flat pad sander produced a much flatter surface than a ROS. However, both required final hand sanding with the grain for optimum appearence. If not hand sanded, swirl scratches would show. Final hand sanding using a sanding pad in the direction of the grain is a must.

   To carry it one step further, sanding at 320-400 grit after the first coat and subsequent coats was the optimum for flattening and smoothing. Any finer and adhesion problems were encountered. Any less and the sanding marks were very likely to show through. No improved appearence was noticed by between coat sanding beyond 400 for varnish. 400 was the sweet spot for thinner finishes. Between coat sanding was always done by hand whether for flattening or for adhesion.

   I think you will find similar thoughts in the popular finishing books but YMMV.

6. 
   gecko | Jan 30, 2004 11:27pm | #6

   I agree with howie, I sand the bare wood to 220 before applying any type of finish, and always go over the surface by hand with the 220 after using 220 on whatever machine you choose. between coats I use 400 on a pad to keep the surface flat, then after the final finish coat you can sand up to 1500 for a relatively glossy finish followed by wax, or even french polish etc.

   Custom Cabinetry and Furniture

   http://www.BartlettWoodworking.com

    

7. 
   Paul_Snyder | Jan 31, 2004 05:17pm | #7

   How fine to sand depends on the wood and the finish you're applying.

   If you're staining the wood and applying a film forming finish (lacquer, waterborne, varnish, poly, etc.), then 150 grit is good in most cases though you may want to go to 180 or 220 on white woods (e.g., maple) to avoid sanding scratches showing up. When using a pigmented wiping stain, sanding with higher grits makes the stain color lighter. Some of the stains I use specify sanding no higher than 120 grit. The "coarser" sanding pattern holds the stain better and ensures the finish will adhere to the wood after staining.

   If you're applying a hand rubbed oil finish then sanding to a higher grit (e.g., 400+) is a good idea and makes for a nicer finish in the end.

   Paul

8. 
   stancalow | Feb 01, 2004 09:11pm | #8

   Aquita

   I'm no expert, but  I agree with Paul S.   I recently made a box of cherry with only an oil finish, and sanded to 1200.  I did it for the feel, not for looks. 

   If I'm going to use a builit-up finish, I go to 220, but use 320 or 400 on the end-grain to help keep it from getting darker than the rest of the surfaces. 

9. 
   Holzbock | Feb 02, 2004 12:13pm | #9

   Hi,

   I made some Billardtool out of ebony, snakewood, grenadill, cocus,...

   very hard woodtyps. The finish was also oil. I never start a finish under 280-sandpaper and in this case, I polished up to 1500, sometimes 2000!!

   Queuefluesterer